Signaling system for two-way dialing over radio and carrier telephone circuits



1948. E. H. B. BARTELINK 2,457,434

' SIGNALING SYSTEM FOR TWO-WAY DIALING OVER RADIO AND CARRIER TELEPHONE CIRCUITS Filed Feb. 20, 1947 2 Sheets Sheet 1 Awro MAT: TELEPHONE Excrmruac:

Lmz: EAST i RADIO STATION l 47 INVENTOR EvERHARb H.B.BARTELINK.

ATTOR N EYS Lama Was-r R 0|o STATION 5 Dec. 28, 1948. BARTELlNK 2,457,434

SIGNALING SYSTEM FOR TWO-WAY DIALING OVER RADIO AND CARRIER TELEPHONE CIRCUITS Filed Feb. 20, 1947 2 Sheets-Sheet 2 Oureome. LINE Iwcommc LINE FILTER. ANDDETEC.

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EvsreraARb H. B.BA RTELINK.

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Patented Dec. 28, 1948 SIGNALING SYSTEM FOR TWO-WAY DIAL- ING OVER RADIO AND CARRIER TELE- PHONE CIRCUITS Everhard H. B. Bartelink, Bronxville, N. Y., as-

signor to General Telephone Corporation, New York, N. Y., a corporation of New York 0, 1947, Serial No. 729,830 ecieims. (01; 250-6) Application February 2 This invention pertains to signaling circuits for use in conjunction with radio or carrier current circuits of automatic telephone systems employing dialing pulses for effecting station selection. A primary object of the invention is to provide novel and relatively simple and economical circuits and apparatus for effecting two-way dialing, supervision and circuit control over radio or carrier current links or channels interconnecting automatic telephone exchanges or central offices.

The invention is grounded on the concepts of switching the carrier current on and off, of interrupting the same in accordance with dialing pulses, and of modulating the same with special tones or frequencies as means for extending the dialing, supervision and circuit control functions over the radio or carrier current links aforesaid.

The invention will be described with particular reference to a two-way radio link interconnecting a pair of automatic central office exchanges, although it will be understood that identical signaling circuit arrangements are applicable to carrier current telephone line circuits, since a two-Way radio link is the substantial equivalent of a two-way carrier telephone line circuit, as regards principles of operation and terminal equipment employed, so that the signaling problems are the same. That is to say, in each instance, and at the terminals of the'radio or carrier link, a two-wire, two-way, voice frequency telephone circuit extends to a hybrid coil, one branch of which connects to the input of the radio transmitter or carrier current oscillator,

whereby the speech input modulates the 'outgoing carrier; While the other branch of the hybrid @coil connects to the output of the radio receiver or carrier current demodulator, whereby the speechmodulated incoming carrier is, after demodulation, transmitted to the two-Wire, voice frequency circuit, It will be evident, therefore, that the :same types of circuits and apparatus will be required for effecting two-way dialing, supervision and circuit control over a carrier current telephone line as is required in the case of a radio link. 1

Since the radio stations or carrier telephone circuit terminals, as the case maybe, are in general located at greater or lesser distances from the automatic telephone exchanges which they serve, I propose, in accordance with the preferred modification of my invention, to connect each radio station or carrier telephone line terminal to its associated automatic exchange, over a pair of two-conductor lines, one an outgoing line to handle calls outgoing from the central ofiice to the radio link or carrier line, and the other an incoming line to handle calls incoming to the central ofiice from the radio link or carrier circuit.

When the system is idle, as well as on outgoing calls, the outgoing line is connected through back contacts of a normally deenergized sequence relay and through a two-winding isolating transformer to the two-wire, speech frequency line extending to the hybrid coil of the radio station or carrier terminal equipment. On incoming calls, however, the sequence relay is energized to transfer the two-wire connection from the hybrid coil to the incoming line, the sequence relay remaining thus operated until the call is completed.

The carrier current of the radio or carriercurrent transmitter. is under control of a transmitter Dialing pulses are transmitted to the relay which, when energized, switches on the outgoing carrier, this relay being sufiiciently rapid in operation to follow dialing pulses. On outgoing calls, the transmitter relay is under control of a fast-operating line relay which responds to dialing pulses received from the central oflice over the outgoing line, and thus, by correspondingly actuating the transmitter relay, transmits the outgoing dialing pulses over the radio or carrier link by interruption of the outgoing carrier.

The line relay is connected to a battery of reversible polarity at the radio station or carrier terminal, and is normally connected to the outgoing line through back contacts of the sequence relay, so that when a call is placed on .the outgoing line, a direct current loop circuit is completed at the central office on this line to energize the line relay, in turn to energize the transmitter relay and thus switch on the outgoing carrier. line relay by interruption of the direct current.

Energization of the line relay energizes a slowacting transmitter follower relay, which is unresponsive to dialing pulses andwhich prevents the sequence relay from operating to disconnect the line relay, in the event an attempt is made to place an incomingcall while an outgoing call is in progress.

The outgoing carrier transmitted to the distant radio station or carrier terminal, operates a carrier current actuated relay thereat. This carrier relay, which is sufficiently fast-acting'to follow dialing pulses, in turn operates a slow-acting carrier follower relay which is unresponsive to dialing pulses. The carrier follower relay in turn energizes the sequence relay at the distant station through contacts of the normally deenergized 1 :naling :ciitcuits f myginventiontin eneral :terms, 3 .during the progress :of establishing a telephone ta..sconnectioninvolizeszthe transmitting equipment transmitter follower relay thereat. Operation of the sequence relay in turn operates the transmitter relay at the distant station to switch on the radio transmitter carrier thereat, and also connects the two-Wire connection from'the hybrid coil thereat to the incoming line extendin to the distant central oifice. .It also. disconnects the line relay thereat and substitutes therefor a two-winding polarized relay, the windings :af which extend at their inner.terminalsltonormally open contacts of the carrier zjre'lay. Z'Ifherefpre, operation of the carrier relayin response'to dialing pulses received over the radio or carrier link, completes through its contacts-and the-polarized relay windings, a loop over the distant i ncoming line for transmitting the dialing'pulsesthereover it'he distant radiolstationser carrier terminal, with .a supervising :frequencyzortone. This. supervision iiirequencyrremains on .untilthe distant ;or::.cal1ed :subscriber lifts. hiszreceiver from-the sWit'C'h'hOOk and thereby reverses the battery:fromqthe distant 1 .rd-ia'l exchange. This :battery reversal operates the polarrelay at the distantradiolstatiomorcartrier terminal, from its spacing :-:to Iits :;marking ccontaet, and thereby disconnects .or removes :the supervision frequency from the .c-arrierincoming to the calling station.

:The supervision frequency is, as :aibov,e exf'pla'inecl, transmitted to :the radio station gorcar rier terminal originating :the wall, whence :upon :demodulation, it energizes .a supervising relay ithereat, whichiin turn zcontrols tthe polarity .of the "battery applied "to the .line relay thereat. 'Thus, the LsuperviSingzrelay '{Wiil apply reverse tbattery through the line relay to the outgoing 'Jlin'e originating :the :call, .until :thecalled station :has answered. When thisaoccurs;theisuperyision frequency will be removed from the'incomingcarrier, as above explained, :thereby "causing 1 the :su-. peryision relay to release'zat the-,originatinglend of the call, and :thus :apply rnorm al battery :to 1 the coutgoing line :connected :to "the calling station.

I 'Thisadvises the .calling station that :the called subscriber has answered.

The above describes "the ;operation :.of the ;;-sig- :ccnnectionyfrom onerautomatic :central office 1 ex- .s'change over tlieiradioior carrier linkrtoadistant automatic exchange. The establishmentof such at tone end of: the radio :;or carrier "link "and ;re-

pceiving-equipment eat the other end thereof. It "will beunderstood,ofcoursegthat since this trans- .m-itting and receiving: equipment is; duplicated at teach end :of theiink, the above generalized description covers the operation oftheatransmita ting equipmenton-outgoing .calls,-a s .well as the operation of theareceiving .equipmentonincomling cal'ls.

:It will be evident qfrom the above generalized description :that the 'signaling circuits of this invention are characterizedbythe following novel 1 ":featuresof'operation. *Anincoming call willpperate :a :sequence' relay and keep. it operated .until the callis completed. Alsoronvincomingcalls,

3.5 eure also 4 the sequence relay will energize the transmitter to transmit the outgoing carrier. When the circuit is being utilized for an outgoing call, the line relay controlling the transmitter follower relay prevents the sequence relay from operating, to establish azconnection foraan incoming call. On .zanaincoming-caH, a supervisiontone is put on the line until the called subscriber removes his reapeiver from the switch hook. On an outgoing .call,. recept i qn of the supervision frequency from :thedistantastation-will control the battery polar- .itity-.-appliedltof.the line relay. Fast and slowoperating relays are employed to transmit dialiingzpulses on'ztl-rezone hand, and to hold circuits during dialingnon the other hand. At the cone=lusion of -anou-tgoing call, a delay relay, prol/.-ided .in.theucircuit and to be described hereinafter, will, by interrupting the circuits until all relays have been cleared, prevent an incoming call im iliicitelephoneexchange, thevlatter being shown tdiaerammatica while ;Figs.-;2 to??? -,i nc.--a1:ecir cuit diagrams of the wsienar inetsystem of. :Fig. 1. -.w, e n. h w ve t separatin iandicentr circu s fQ v i u of t individual relays are separately illustrated. Fig. 2 gshewsfiihfi radioztran mitting-andreceiving station Iii-1 ssimnlified :icr .bee h @wi c t s wther rcm to ithe :mcQmine --and out in lines, cl dingrtheeepe at ne w nd .car i' r a dvs n v s e r y t he spurce f sun rv i n r que y- .iE'ig. :gShfiWS operating circuits fora-theseq nge relay; Eig. 4 those for the transmitter :5 tha vfe the transm tter o w -6 that tor -;the carrier f ollower relay; hatfiqrz adelay relayefer zin t :;th,e-:.-d av nes. andz part cular y t A 11, the ein shown-a radio s ati and a p rtie. fq tradi us t on EB, com risin w w y ka Ac mprises arad otd phme i eci ve a a d :11 rad o t phonewtr nsmitter Z 'Ih twice i equeney outp t-cf -:th.e re ve a d rrthewvo ee frequen y in u o the tr smit r a enmeshedres ecti e y 4W?! .c. r du tcrs .13, 1* a hmueh h id c411 fltea tw -Wire line nezt nect dztmteueh-atw w n i ud frequenqypztransformer shandsoverra $132.11 or .coneducters :8. etc 'sthe uarmatures Be-.2, S43 of 1 the -n mally tieenereizedzsequence IIElf JY'fik r nt ()0 iterminates JOI'I 's-incoming zterminal gequipment ,l l,

twhile ithe coutgoing :tl-ine 'terminates on outgoing -=.termina1-lequipmenti-Il2. ifhetterminals l l, 12 are :iinked ate .the :ldialeaetuated selecting equipment 1.:t3 ofthewautomatic iexchangefltoiwhich the sub- ".scribers zstations, such :as 14, .are connected.

The two-winding transformer 1 serves to sepea'natetlthe- :voice frequencywcircuittfrom the. direct acnnrentsdialing andwsignaling .circuits. To this Lend, thene interposedwatthe midpoint of the 7o wtransformen-win'ding t5.-a condenser t6, the opposite terminalslof which arerrespectively connected :-.to anmatures:isnmnseeaofthe sequence relay S, the back contaots ..:of which ar-matures are respectively tconnected to winding terminals of a 76 twoewindingiline relay-iii, whilethe front contacts of said armatures are respectively connected to winding terminals of 'a two-winding polar relay P. Thus, when relay S is deenergized, the speech circuit 6, 1, 8 is connected to the outgoing central office trunk line H], the direct current signaling circuit of which includes, at the radio station, the line relay L. Contrarywise, when relay S is energized, the speech circuit 6, 1, 8 is connected to the incoming trunk line 9, the direct current signaling circuit of which includes the polar relay P. The functions of these relays have been touched upon in the foregoing general description of the invention and will be explained more in detail hereinafter. 1

The remaining portions of the circuit, together calls outgoing from radio station A to radio station B.

Incoming calls On incoming calls, the carrier current actuated relay C, connected to the radio receiver I, is energized by carrier current transmitted from the radio transmitter of station E. Relay C is a quick-acting relay which follows the dialing pulse interruptions of said carrier current. Operation of relay C connects ground at its grounded armature C-I to the carrier follower relay CF to energize the same from battery H. The CF relay is of the slow-release type, such that it will remain operated during reception of dialing pulses, actuatin relay 0.

If radio station A is not in use when incoming carrier current is received from station E, the CF relay, upon operating, will energize the sequence relay S, over a circuit traced from the grounded armature CF--I and front contact of the CF relay, thence through the upper armature D2 and back contact of the normally released delay relay D, thence through the armature TF-'i and back contact of the normally released, transmitter follower relay TF, and thence through the winding of the S relay to the negatively grounded battery H3. The operation of the S relay over the circuit traced, will complete a holding circuit for thereafter holding the S relay operated under control of the CF relay, this holding circuit being traced from battery I8 through the winding of the S relay and thence through its front contact and armature S-lover connection [9 to ground through the front contact and grounded armature CF--l of the CF relay. As explained below, the S relaycan not be operated over the circuit above traced, if radio station A is/busy when an incoming call is received from station B, because, in that event, the transmitter follower relay TF will be operated, and will thus open at its TF-l contacts, the operating circuit of the S relay above traced.

The operation of the sequence relay S completes an operating circuit for the normally deenergized, transmitter relay T, energization of which in turn completes, through its armature T! and front contact, a connection 20 which switches on the carrier of radio transmitter 2, and thereby transmits outgoing carrier to the radio receiver at station B. The operating circuit for the T relay is traced from the negatively grounded battery 22, thence through the T relay winding and over connections 23, 24, through the lower back contact and armature D-l of the normally deenergized delay relay D, and thence over connection'25 to the front contact armature S-(S of the S relay.

Relay S in operating also transfers at its S-Z, S3 contacts, the speech circuit 6, l, 8 from the outgoing central oflice trunk line ill to the incoming line 9; and concurrently disconnects at its contacts S4, 5-5, the line relay L from the direct current signaling circuit, and substitutes therefor the polarized relay P. It will be noted that the inner terminals of the polar relay windings are connected respectively to the C2 armature and associated front contact of the carrier relay C.

The polar relay P provides reverse battery supervision of the connection over the incoming line to the telephone exchange E, while the con tacts C--2 of the carrier relay C, busies the line and transmits the dialing pulses to the exchange in response to dialing pulse interruptions of the carrier transmitted from radio station B to radio station A. So long as the polar relay P receives normal battery current or no current, its armature P-l will make contact with its upper or spacing contact. This prepares a circuit, completed upon operation of the S relay, for applying a supervision frequency f-S from one oscillator 26 to the input of radio transmitter 2, for transmission to the distant radio station B. This circuit is traced from the upper terminal of oscillator 26 over conductor 21 through the S-'! armature and front contact of the S relay, thence through the spacing contact and Pl armature of the P relay, thence over conductor 28 and through a resistance 29 to one side of the radio transmitter input circuit 4, the opposite side of which is connected through a similar resistance 30 to the opposite terminal of oscillator 20.

This supervision frequency remains on the line until the called subscriber, such as M, removes his receiver from the switch hook and, by so doing, reverses the battery applied over the incoming line 9 from the dial telephone exchange E. This battery reversal operates the polar relay P from its upper or spacing contact to its lower or marking contact, thereby to disconnect the f-S oscillator 26.

Energization of the C relay by the incoming carrier from station B has, by closing its C-2 contacts, prepared for dialing, the loop which includes the polar relay, the upper and lower halves of winding [5 of transformer 1, and the incoming line 9 extending into the central oifice. In addition, dialing tone is now received from telephone exchange E over line 9, which is transmitted over the speech circuit 5, I, 8, through hybrid coil 5, and over line l to the input of radio transmitter 2, for radio transmission to the radio receiver of station E, and thence over the associated outgoing trunk line to the automatic exchange at the calling end and thence to the calling subscriber. Upon receipt of the dial tone transmitted in this way, the calling station reand grounded ceives a signal that the connection is ready for dialing, so that the calling station may now proceed to dial. This operates the C relay at station A according to the digits dialed. As stated, the CF relay is sufficiently slow in operation to remain operated during this dialing process.

Upon completion of the call, when the calling subscriber hangs up, the carrier current transmitted from station'B to station A is switched off (as will be explained below in connection with calls outgoing from station A), resulting in the release of the C relayat station A, the release of which in turn releases relays CF, S and T, thereby restoring the signaling system "at station A to normal.

If the subscriber at the called end, such as M, should-hang up before the calling subscriberdoes,

this will again reversethe battery applied at the telephone exchange Etc the incoming'linet, the

resu-lting'current reversal of which in the .polar relay P will return its armature from its marking to its spacing contact. This in turn will put supervision frequency f-S from the oscillator 2 back on the line. 3

It is to be noted that the-supervision frequency can be transmitted from station A only on calls incoming thereto from station E, since'it is-only on such calls that the 'S relay is energizedto connect the ,f-S oscillator 26 to thetransmitter 2. As will be explained below, in connection with callsoutgoing from station A, the S relay thereat will remain deenergized during the entire call.

Outgoing calls On outgoing calls, the dial telephone-exchange E is connected, as above explained, to radio station A over the outgoing trunk l0, and thence through the armatures and back contacts 'S-Z, S--3 of the normally released S relay, to line 6, l, 8. Thus, the voice frequency circuit from exchange Eis connected directly tothe hybrid coil 5 of the radio station. Also, the direct current signaling circuits of line H) are connected to the line relay L via the armatures and back contacts S'2, S-3, S l, S--5 of the sequence relay S.

The line relay is energized over this circuit from batteryfii, connected across the inner terminals of the line relay windings, through contacts and armatures SR-l, SR-Z of the supervision'relay SR. Battery 3| is connected in one polarity through the back contacts. of these armatures, and is connected in the opposite polarity through the front contacts thereof. Thus, operation of the SR relay reverses the battery applied to the outgoing line. The SR relay is energized by the supervision frequency is transmitted from radio station B, in the manner above explained in connection with calls incoming to'station A, and to this end is connected to the output of radio receiver I through a filter and detector circuit 32, which transmits only the supervision frequency. The SR relay is thus normally deenergized to impress battery of normal polarity on the outgoing line H), but operates upon receipt of the supervision frequency to reverse the battery p0- larity until the'callecl subscriber answers. However, thesebattery reversals do not release the L relay, which remains continuously energized until the called subscriber hangs up.

When'the line relay L is thus'energized upon receipt of a call incoming from exchange E, it energizes the transmitter follower relay TF over a circuitextending from the negatively grounded battery 33 through the TF relay winding, and

thence to ground through the front contact and station E for the duration of the outgoing call.

A'second contact-of the L relay closes a circuit for the transmitter relay T, traced from the T relay winding, over connection 23, and through the front contact :andarmature Ir-l of the ,L relay, and thence to ground through the back contact and grounded armature-S-li'of the 'now deenergized S relay. The resulting operation-of the T relayswi-tches on the carrier of the radio transmitter 2, as above explained, to provide outgoing carrier to station B.

When the outgoing-dial pulses arenowre'ceived from telephone-exchange E, they will be transcorrespondingly-operate the T relay. Operation of the T relay in response to these dialing :pulses thus interrupts the carrier transmitted to station '13, which in turn'causes the C relay thereat to correspondingly operate andrelease, the transmission-of the dial pulses thence to the calling station being the same as that above described for calls incoming to station A.

Throughout'the call outgoing from station -A, the S relay is, as above explained, continuously deenergized, and therefore the supervision frequency of oscillator '26 will not be transmitted to station B on outgoing calls. On the other hand, station .13 operates as above described in connection with calls incoming to station A. That is to say, it will transmit supervision frequency to station A until the called subscriber has answered, thus operating the SR relay'at station A to reverse thebattery-applied to the outgoing line from source M. In addition, the-central ofli'ce connected to station B will return dial tone to the subscriberoriginating the call, and connected to exchange E'. v

v The operation of the line relay L on outgoing callsalso operates the delay relay D, which latter will remain operated for some time'a'fter completion of the outgoing call, in a manner and for reasons now :to be explained. The Drelay is connected in the plate circuit of an electronic tube '34, andis-energized therein from the negatively grounded .plate battery 35. The cathode of tube34 isenergized over a circuit extending from ground through a low voltage, direct or alternatingcurrent source 35, and thence to the cathode, and over conductor 31 through a front contact of the L relay, the associated armature L-3 of which is grounded. A resistance 38 is bridged between this armature and-its associated front contact for normally energizing the oathode of tube 34 to some extent, but insufficient to energize the D relay, while the line relay is released. Upon operation of the line relay, however, this resistance is shuntedout by the relay contacts, whereupon the cathode of tube 3:8 is

energized sufliciently to operate relay D. Upon subsequent releaseof the line relay-however, the D relay 'will not release for some time thereafter and until the'cathode of tube 34 has cooled sufficiently to reduce the plate current of the tube below the release current for the D relay. The :purpose of this delay in the release of the D relay following the release of the L 'relayat the conclusion of an outgoing call, is to delay the operation of the circuit-on subsequent incoming calls for a sufiicient lengthof time to assure that all oth'er'relays are restored to their normal con- :ditions, particularly the T and S relays, the operating circuits of which are under control of the D "relay upon release of the "L rel'ay. An additional purpose for thus delaying the release 'of'the D relay isto'prevent locking. of the radio system, i.='e., energization of 'the S relays at both stations A-and B.

(")n incoming calls, operation of the S relay, as above explained, completely disconnects the line relay L at the -4, 8-5 contacts of the S relay. This prevents operation of either the delay relay D or the transmitter follower relay TF for the duration of an incoming call, since the operating circuits for both of these relays are completed through contacts of the line relay.

The separate wire circuits 9 and. ID for handling incoming and outgoing calls, between the central ofice and the radio station, may of course be replaced by a single two-wire circuit, inasmuch as all of the functions of two-way dialing and supervision are provided by the relay circuits included in the radio station terminal equipment, in which event this single two-wire circuit from the central ofiice would become permanently connected to line 8, and contacts S2, S-3 of the S relay omitted.

I claim:

1. In a two-way dial telephone signaling system for relaying signals between a low frequency wire circuit and a carrier wave circuit: a carrier wave transmitter and receiver; a carrier relay responsive to carrier current incoming to said receiver and to dialing interruptions thereof; a slow-release relay responsive to said carrier relay and unresponsive to dialing signals; a sequence relay energized by said slow-release relay for connecting said wire circuit to contacts of said carrier relay for repeating in said circuit the dialing pulse operation of the carrier relay; a line relay; means including release contacts sequence relay for connecting said line relay to said wire circuit, said line relay responding to dialing pulses incoming over said wire circuit; and means including said line relay for energizing said carrier Wave transmitter, to transmit outgoing carrier and for interrupting the same in response to dialing signals incoming over the wire circuit.

2. In a two-way dial telephone signaling system for relaying dialing signals between a low frequency wire circuit and a carrier wave circuit: a carrier wave transmitter and receiver; a carrier relay responsive to carrier current incoming to said receiver and to dialing interruptions thereof; a slow-release relay responsive to said carrier relay and unresponsive to dialing signals;

a transmitter relay for energizing said transmitter to transmit outgoing carrier, said relay responding to dialing signals; a sequence relay energized by said slow-release relay for energizing said transmitter relay and for connecting said wire circuit to contacts of said carrier relay for repeating in said circuit the dialing pulse operation of the carrier relay; a line relay; means including release contacts of sequence relay for connecting said line relay to said wire circuit, said line relay responding to dialing signals incoming over said wire circuit; and means including said line and transmitter relays, for interrupting the outgoing carrier in response to dialing signals incoming over said wire circuit.

3. In a two-way dial telephone signaling system for relaying signals between a low frequency wire circuit and a carrier wave circuit; a carrier wave transmitter and receiver; a. carrier relay responsive to carrier current incoming to said receiver. and to dialing interruptions thereof; a slow-release relay responsive to the carrier relay and unresponsive to dialing signals; a transmitter relay for energizing said transmitter to transmit outgoing carrier; a sequence relay energized by said slow-release relay for energizing said transmitter relay and for connecting said wire circuit to contacts of said carrier relay for repeating in said circuit the dialing pulse operation of the carrier relay; a line relay and a transmitter follow relay; means including release contacts of said-sequence relay for connecting said line relay to said Wire circuit and for energizing the same; said transmitter follow relay responding to energization of said line relay to prevent energization of said sequence relay while the line relay is actuated; said line and transmitter relays responding to dialing signals incoming over said wire circuit for correspondingly interrupting the carrier outgoing from said transmitter.

4. In a two-way dial telephone signaling system for relaying signals between a voice frequency wire circuit and a carrier wave circuit: a carrier wave transmitter and receiver; a carrier relay responsive to carrier current incoming to said receiver and to dialing interruptions thereof; a slow-release relay responsive to said carrier relay and unresponsive to dialing signals; a transmitter relay for energizing said transmitter to transmit outgoing carrier; a sequence relay energized by said slow-release relay for energizing said transmitter relay and for connecting said wire circuit to contacts of said carrier relay for repeating in said circuit the dialing pulse operation of the carrier relay; a line relay; means including release contacts of said sequence relay for connecting said line relay to said wire circuit; a slow-release transmitter follow relay responsive to said line relay, when energized, for preventing energization of said sequence relay; means including operate contacts of said line relay for energizing said transmitter relay, said line and transmitter relays responding to dialing signals incoming over said wire circuit for repeating said signals in the outgoing carrier; a delay relay; and means including operate contacts of said line relay for energizin said delay relay, said means thereafter delaying release of said delay relay for a preselected interval following deenergization of said line relay.

5. In a two-way dial telephone signaling system for relaying signals between a low frequency wire circuit and a carrier wave circuit: a carrier wave transmitter and receiver; a carrier relay responsive to carrier current incoming to said receiver and to dialing interruptions thereof; a slow-release relay responsive to said carrier relay; a transmitter relay for energizing said transmitter to transmit outgoing carrier; a polar relay; a sequence relay energized by said slow-release relay for energizing said transmitter relay and for connecting said wire circuit to contacts of the carrier relay through windings of the polar relay for repeating in said circuit the dialing pulse operation of said carrier relay; said polar relay being unresponsive to voltage of one polarity impressed on said wire circuit, but responding to voltage of the opposite polarity impressed thereon; a source of supervision frequency; means including release contacts of said polar relay and operate contacts of said sequence relay for impressing said supervision frequency on said transmitter to modulate the outgoing carrier thereof; a line relay; means including release contacts of said sequence relay for connecting said line relay to said wire circuit; a voltage source for energizing said line relay over said wire circuit when so connected; a supervision relay energized by supervision frequency incoming to said receiver, for impressing said Voltage source in one polarity on said line relay, and for 11 reversing said polarity upondeenergizationf of said supervision relay; and means includingfoperate contacts of said line relay for energizing said transmitter relay, said line and transmitter relays responding to dialing pulses incoming over said wire circuit for correspondingly interrupting the carrier outgoing from said transmitter.

6. Ina llWO-WfiYdifil telephone signaling system for relaying signals betweenalow-frequency wirecircuit and a carrier wave circuit: a carrier wave transmitter and receiver; an incomin and an outgoing wire circuit; a carrier relay responsive to carrier current incoming to said receiver and to dialing interruptions'thereof; a slow-re lease relay responsive to said carrier'relay; a transmitter relay for energizing said-transmitter to transmit outgoing carrier; .a sequence relay energized by said slow-release relay for energizingsaid transmitter relay and for connecting said incoming circuit to contacts of said carrier relay for repeating in said circuit the dialing pulse operation of said carrier relay; a line relay; means including release contacts of said sequence relay, for connecting said line relay to saidoutgoin circuit, and for energizing said relay; and means. including operate contacts of said line relay,- for energizing said transmitter relay, said line andtransmitter relays responding to-di'aling pulses, for interrupting the outgoing carrier in response to dialing signalsreceivedover 'said outgoing line. 1 V i 7. In a two-way. dial telephone signaling system for relaying signals between a low-frequency Wire circuit and. a carrier: wave circuit: a carrier Wave transmitter andreceiver; an' incoming and an outgoingwire circuit; a carrier relayresponsive to carrier current incoming to said receiver and to. dialing interruptions thereof; a slowrelease relay responsive tosaid carrier relay a transmitter relayfor energizing said transmitter to transmit outgoing carrier; a sequence relay energized by said slow-release relay 'for' enere gizing saidtransmitter relay and for connecting said incoming circuit to contacts of said" carrier relay for repeating in said circuit the dialing pulse operation of said carrier relay; a line relay; means including release contacts of sa-id sequence relay, for connecting said line relay to said line outgoing circuit, and iorenergizing said relay; means including operate contacts of said, line relay, for energizing said transmitter relay, said line and transmitter relays responding to dialing pulses, for interrupting the outgoing carrier in response to dialing signals received over said outgoing line; and-a transmitter follow relay, responsive to said line-relay, for preventing operation of said sequence-relay during" energization of the line relay.

8. In a two-way dial telephone signalingzsystem for relaying signals between a low-frequency wire circuit and a carrier'wave circuit: a carrier Wave transmitter and receiver; an incoming and an outgoing Wire circuit; acarrier relay responsive to carrier current incoming to said receiver and to dialing interruptions thereof; a slowrelease relay responsive tosaid carrier relayra;

transmitter relay for energizingsaid transmitter j to transmit outgoing carrier; a sequence relay energized by said slow-release relay for energizing said transmitter relay and for connecting 3 said incomin circuit to contacts of saidcarrier relay for repeating in said circuit the dialing pulse operation of said-carrier relay; aline rel lay; means including; release contacts-of said sequence relay, 'for connecting said line relay to said outgoing circuit, and for energizing said relay; means includingoperate contacts of said line relay, for energizing said'transmitter relay, said line and transmitter relays responding to dialing pulses, "for interrupting the outgoing carrier in response to dialing signalsreceived over said outgoing line; a transmitter follow relay; responsive tdSaidlinerelay, for preventing operation of said sequence relay during energizationof the line relay; and-"means including adelay relay'responsive to operation of said line relay, said means thereafter delaying release of said delay relayfor-a preselected interval following "releaseof saidline relay.

9. In a two=way dial telephone signaling system for relaying signals between a'low-frequency Wire circuit and a carrier wave circuit-'1 a carrier wave transmitter and receiver; anincoiningand an outgoingwire circuit; a carrier relay responsive to carrier current incoming to said-receiver and to dialing interruptions thereof; a slowrelease relay responsive tos'aid carrierrelay; a transmitter relay foreriergiz'in'g said transmitter to :transmit outgoing carrier; a polar relay;- a sequence relay energized by said slow-release relay for energizing said transmitter relay and for connecting said incoming circuit to contacts of said carrier relay through windings of the polar relay for repeating insaid circuit thedialing pulse operation of said carrier relay, said polar'relay being unresponsive to voltage of one polarity impressed on said incoming circuit, but responding to voltage of the opposite polarity impressedthereon; a sourceof supervision frequency," means including release contacts of said polarrelay and operate contacts ofsaid sequencerelay, for impressing sa'id supervision frequency on" saidtransmitter to modulate the outgoing carrier thereof; a line relay; means including release contacts of said sequence relay for connecting said line relay to said outgoing circuit; a voltage source for energizing said line relay over said circuit when so connected; a supervision relay energized by supervision frequency incoming to said receiver, for impressing said voltage source, in one polarity on said line relay, and for reversing said polarity upon release of said supervision relay; and means including'said line relay for energizing said transmitter relay, said line and" transmitter relays responding to dialing pulses, forv interrupting the outgoing carrier in response to dialing signals received over said outgoing, line.

' EVERHARD H. B. BARTELINK.

REFERENCES" crrEn The followingreferences are of record in the file of this patent: V g

UNITED STATES- PATENTS JDec.. 23,, 19,47,

Disclaimer 2,457,434.Everha1"d H. B. Bartel'ink, Bronxville, N. Y. SIGNALING SYSTEM FOR Two-WAY DIALING OVER RADIO AND CARRIER TELEPHONE CIRCUITS. Patent dated Dec. 28, 1948. Disclaimer filed Nov. 8, 1950, by the assignee, Automatic E Zeetm'o Laborato'm'es, I no. Hereby enters this disclaimer of claim 1 of said patent.

[Ofice'al Gazette December 5, 1950.] 

